Regulation of the contraction induced by emptying of intracellular Ca2+ stores in cat gastric smooth muscle.
- Author:
Hye Jung BAEK
1
;
Sang Soo SIM
;
Duck Joo RHIE
;
Shin Hee YOON
;
Sang June HAHN
;
Yang Hyeok JO
;
Myung Suk KIM
Author Information
1. Department of Physiology, College of Medicine, Catholic University of Korea, 505 Banpo-dong, Socho-gu, Seoul, South Korea.
- Publication Type:Original Article
- MeSH:
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine;
Animals;
Calmodulin;
Cats*;
Genistein;
Isometric Contraction;
Muscle, Smooth*;
Phosphotransferases;
Protein Kinase C;
Protein Kinase Inhibitors;
Protein-Tyrosine Kinases;
Trifluoperazine;
Type C Phospholipases;
Verapamil
- From:The Korean Journal of Physiology and Pharmacology
2000;4(2):113-120
- CountryRepublic of Korea
- Language:English
-
Abstract:
To investigate the mechanism of smooth muscle contraction induced by emptying of intracellular Ca2+ stores, we measured isometric contraction and 45Ca2+ influx. CaCl2 increased Ca2+ store emptying- induced contraction in dose-dependent manner, but phospholipase C activity was not affected by the Ca2+ store emptying-induced contraction. The contraction was inhibited by voltage-dependent Ca2+ channel antagonists dose dependently, but not by TMB-8 (intracellular Ca2+ release blocker). Both PKC inhibitors (H-7 and staurosporine) and tyrosine kinase inhibitors (genistein and methyl 2,5-dihydroxycinnamic acid) significantly inhibited the contraction, but calmodulin antagonists (W-7 and trifluoperazine) had no inhibitory effect on the contraction. The combined inhibitory effects of protein kinase inhibitors, H-7 and genistein, together with verapamil were greater than that of each one alone. In Ca2+ store-emptied condition, 45Ca2+ influx was significantly inhibited by verapamil, H-7 or genistein but not by trifluoperazine. However combined inhibitory effects of protein kinase inhibitors, H-7 and genistein, together with verapamil were not observed. Therefore, this kinase pathway may modulate the sensitivity of contractile protein. These results suggest that contraction induced by emptying of intracellular Ca2+ stores was mediated by influx of extracellular Ca2+ through voltage-dependent Ca2+ channel, also protein kinase C and/or tyrosine kinase pathway modulates the Ca2+ sensitivity of contractile protein.
